BSIP 65: fix locked accounts / recursive account permissions

Earlier discussion is here: https://github.com/bitshares/bitshares-core/issues/269

We do need to identify the locked accounts first.

After identified, an approach to fix them is reverting the last `account_update_operation` done in the accounts.

Start by reading the earlier discussion in BitShares issue 269 and the account permission behavior described here. Identify which accounts are locked and determine whether reverting each account's last account_update_operation resolves the recursive permissions; done means the affected accounts are identified and a concrete fix approach is established.

Written by the indexing model from the issue text.